Display read-only state of open files using a lock icon

[bjorn]

This should be mostly helpful for people using a VCS like Perforce or Subversion, which may require a file to be checked out or locked before it can be edited.

For now the read-only icon is a lock, which is common, but it may be confusing for Subversion users since they actually need to lock the file to make it writable.

[eishiya]

The lock is displayed for maps that have not been saved to a file, which doesn't feel appropriate. It makes some sense, the maps do have to be Saved As to write the changes since they can't be Saved normally, but presenting the file as locked/read-only doesn't seem a good fit.

I think it's been discussed before that Tiled probably needs to present unsaved files in some different way, e.g. "Unsaved map" instead of "untitled.tmx", which implies a file that doesn't exist. Perhaps an alternative is to use a different icon for unsaved documents, such as the new document icon.

[bjorn]

The lock is displayed for maps that have not been saved to a file

Thanks for catching that! It actually happens because internally read-only is set to !file.isWritable(), which obviously will be true for files that do not exist. I'll extend that with a file exists check.

I agree the unsaved map could be better identified, though the use of "untitled" as file name for unsaved files seems to still be quite ubiquitous. What about just "New Map"?

[eishiya]

"Untitled" as a file name is ubiquitous, yes, but there's no file, and therefore no file name xP "New Map" would work. Even "Untitled" might be fine, the main thing is to get rid of the file extension that implies there's a file.